This invention relates generally to devices which may be controlled by infrared signals.
A variety of electronic devices are controlled by infrared signals. For example, television receivers may be controlled by a remote control which generates unidirectional infrared signals to control the settings of the television receiver. In addition, a number of processor-based systems, such as set-top computer systems, may be controlled using infrared remote control units. For example, a television receiver may be controlled by infrared transmissions, which may be communicated from a remote control unit or a set-top computer system situated on the television receiver.
The set-top personal computer system may be used to access Internet information that is viewed on a television receiver. In one embodiment, the set-top computer system may access an Internet site containing information about currently available television programs. The set-top computer may then convey-control signals via an infrared transmitter and cable to an infrared detector on the television receiver to control the timing of the television receiver based on inputs received from the user. Thus, as the user inputs commands to select a particular program displayed on the television receiver by the set-top personal computer system, the television tuner may be operated to select the desired program.
In many cases, the set-top computer provides an electronic signal to the television receiver, which may be conveyed through a cable. On its end remote from the computer system, the cable may include a transducer which converts electrical signals into infrared signals. These infrared signals are then blasted into the infrared detector on the television receiver. Commonly, the transducer is secured to the infrared detector cover using adhesive attachment. Thus, the commands from the set-top computer can be blasted directly into the television""s infrared detector.
While infrared signals are being blasted directly from the set-top computer into the infrared detector on the television, the user may also operate a remote control-unit which similarly sends infrared signals that are received by the same infrared detector. These signals from the remote control unit interfere with the commands being transmitted by the computer system.
To overcome this problem, it is known to cover the television""s infrared detector and common infrared transmitter with tape so only those signals transmitted from the set-top computer over a cable are received by the detector. Although this solves the interference problem, it creates another problem. In many cases, when the set-top personal computer is not sending commands to the television receiver, it is desirable to control the television receiver using the television remote control unit. While many of the same operations may be done using a remote control unit provided with the set-top personal computer system, some users may prefer to directly control the television receiver, without using the computer system. When the detector is taped over, this is not possible.
Thus, there is a need for a way to allow remote control units to be utilized in conjunction with set-top personal computer systems to control television receivers and other consumer electronic devices.
In accordance with one embodiment, a shutter for an infrared detector includes a cover arranged to be mounted over the detector. An infrared port is formed in the cover. The infrared transmissivity of the port is selectively, electrically alterable.